importing library.xml crashes iTunes

Greetings.

Trying to set up music on an Mac mini using Yosemite & iTunes v12.5

Have added music (almost 300gb, via an external harddrive) to iTunes.

Have a (70mb) library.xml file from 2014 which has lots of playlists that I had created over the years prior.

Trying to "import playlist" that file, after a long attempt either crashes iTunes or comes back with "unknown error (-50)

I have various .itl files as well, but nothing happens (No playlists added) when "import playlist" any of those.

Have run "Organize library" in case that might help, also restarted everything, disconnected reconnected harddrives, but no joy.

I know the playlists are on that . xml file as searching for a specific name of a playlist brings that file in computer search results.

I'd be grateful for any suggestions!

Thank you.

To be imported file was on the harddrive. Also copied to the computer music folder tried it from there.

A new file created was also in the computer music/itunes folder despite music files being on the external harddrive (changed location on the settings)

Am currently stuck waiting for it to go through folder reorganisation possibly a few hours.

I'll try the restart option once it's done.